The future of robotics might have just gotten squishier, thanks to a new phase-changing material from MIT. Made cheaply from items you could buy at a craft store, the material can shift between rigid and soft states on command—meaning it may one day be used to create robots that can squeeze underneath collapsed buildings, or even travel through your blood stream.

Annette Hosoi of MIT and her former engineering graduate student, Nadia Cheng, initially set out in hopes of finding a material that could act like an octopus—capable of deforming itself to pass through through tight crevasses, but still strong enough to exert a force on its environment.

Up until now, the right material had been elusive. Take a bowl of Jell-O, as Hosoi uses to explain the problem: you can squeeze Jell-O into just about anything, but good luck using it to pick up a hammer, or to open a window. But with a little of foam and wax, Hosoi and her colleagues were able to squeeze past the problem.

Here’s Evan Ackerman, writing for IEEE Spectrum:

The MIT approach (which we like to call on-demand squishiness) involves taking a material or structure that’s inherently soft and modifying it with another material that can phase change between hard and soft states. In this case, MIT is using a scaffold made of foam that’s been coated with wax. Wax, being wax, transitions between solid and liquid at a relatively low temperature. When the wax is cold and solid, the foam structure is rigid, but if the wax is heated to soften it, the entire foam structure becomes soft as well.

The researchers also demonstrated that by selectively deforming parts of a structure, they could create joints and make the structure move using a cable (as seen in the video). We’re guessing that as a next step several of these deformable structures could be combined to create a robot that can crawl and squeeze into tight spaces.

Another big advantage of the wax/foam composite material is that it heals itself. If it fractured, an operator could simply target the affected area with heat, and the break would smooth right over.

Tiny, squishy robots might one day be able to navigate through the human body, administering medicine without causing damage to other tissues. Swap out the wax for something a bit stronger, like solder, and a phase-changing robot could be indispensible in rescue situations—deforming to crawl under piles of wreckage, then springing back to a rigid state to clear the rubble from the inside.